1) Field of the Invention
This invention relates to a method for manufacturing a thin film magnetic head.
2) Related Art Statement
In a manufacturing method of a thin film magnetic head, normally, a second magnetic film serving as a top magnetic film is formed after a first magnetic film (bottom magnetic film), a gap film, an insulating film to support a coil film are formed on a wafer. Moreover, in the case of forming the second magnetic film, a plate underfilm is formed on the whole surface of the wafer including the insulating film by a sputtering method, etc. Subsequently, a positive type photoresist is applied on the surface of the plate underfilm and is processed by a photolithography method to form a resistframe for forming the second magnetic film. Then, the second magnetic film is formed in the area enclosed by the positive type resistframe by an electroplating ,etc. A film composed of the material constituting the second magnetic film is plated in an area beyond the positive type resistframe, but it is removed.
In the second magnetic film-forming process, however, there is a problem due to the positive type resistframe. That is, an exposing light in the photolithography process to form the positive resistframe is reflected at the surface of the plate underfilm and then, the reflected exposing light reaches an area beyond a photomask-defining area and exposes the positive type photoresist around the area, resulting in the degradation in the pattern precision of the positive type resistframe and the second magnetic film.
The degradation of the pattern precision is conspicuous at the pole portion of the second magnetic film. The pole portion of the second magnetic film is opposed to the first magnetic film via the gap film. On the backward area from the pole portion is positioned the insulating film rising up with an inclination of a given angle from the surface of the gap film. The starting point of the rising up corresponds to a Throat Height zero point and the rising up angle corresponds to an Apex Angle.
The second magnetic film constitutes the pole portion parallel to the gap film and the first magnetic film up to the Throat Height zero point and then, rises up with an inclination of the Apex Angle toward the top surface of the insulating film from the Throat Height zero point.
Thus, in the case of fabricating the positive type resistframe for forming the second magnetic film by the photolithography process, the positive type photoresist stuck on the inclined portion at the Apex Angle toward the top surface of the insulating film must be exposed.
In this case, the plate underfilm stuck on the inclined portion reflects the exposing light. The part of the reflected exposing light reaches the pole portion. Thus, the exposed pattern of the pole portion is different from that of the photomask, resulting in the pattern destruction in the portion of the positive type resistframe corresponding to the pole portion.
The pattern destruction of the positive type resistframe has difficulty in developing a recording density by narrowing a recording track width up to not more than 1.0 xcexcm.
To narrow the recording track width, Kokai Publication Kokai Hei 7-225917 (JP A 7-2259917) discloses that before forming the second magnetic film, a second pole portion and a back gap portion are formed, and then, a yoke portion composed of the second magnetic film is formed. That is, the document discloses that the second pole portion and the second yoke portion composed of the second magnetic film are formed independently. In the thin film magnetic head described in the above document, the yoke portion composed of the second magnetic film rises up backward from the second pole portion. For improving transmission efficiency of writing magnetic flux, it is desired that the second yoke portion has its almost vertical end (almost parallel end to an air bearing surface (hereinafter, called as a xe2x80x9cABSxe2x80x9d)).
However, when the resistframe for forming the second yoke portion is formed of a positive type resist material, the exposing light exposes the area for the second yoke portion to be formed, to degrade the pattern precision of the positive type resistframe. As a result, it is difficult to form, almost parallel to the ABS, the end of the second yoke portion in the side of the ABS.
It is an object of the present invention to provide a manufacturing method in which a thin film magnetic head is formed so as to have a second yoke portion with a vertical end (parallel end to an ABS) in the side of the ABS, in forming its second pole portion and the second yoke portion independently.
To achieve the object, this invention discloses two types of manufacturing method of the thin film magnetic head.
The first type of manufacturing method relates to a method for manufacturing a thin film magnetic head comprising a slider having an air bearing surface on its medium opposing surface and a thin film magnetic head element having a first magnetic film, a coil film, an insulating film, a gap film and a second magnetic film,
the first magnetic film including a first pole portion composed of its edge portion in the side of the air bearing surface and a first yoke portion continuing to the first pole portion and extending backward from the first pole portion,
the gap film being provided at least on the first pole portion, the insulating film being provided above the first yoke portion and supporting the coil film,
the second magnetic film including a second pole portion opposing to the first pole portion via the gap film and a second yoke portion of which one end continues to and rises up on the second pole portion and of which the other end is joined with the first yoke portion at its rear portion, comprising of the steps of:
forming, after forming the first magnetic film, the gap film, the coil film, the insulating film and the second pole portion, a plate underfilm on their exposed surfaces,
applying a negative type photoresist film on the plate underfilm,
forming a resistframe to define a pattern for forming the second yoke portion through exposing and developing for the negative type photoresist film, and
forming a plate film to constitute the second yoke portion.
As mentioned above, in the first type of manufacturing method, the negative type resistfilm is applied on the plate underfilm, and thereafter, is exposed and developed to fabricate the resistframe to define the pattern to be used in forming the second yoke portion.
According to the above manufacturing method, in forming the resistframe to define the pattern to be used for the second yoke portion, an exposing light for the negative type resistfilm is irradiated to the area except the pattern for the second yoke portion, which is quite different from the above conventional manufacturing method in which the exposing light is required to be irradiated to the area within the pattern for the second yoke portion. Therefore, the exposing light is not reflected at the plate underfilm within the pattern for the second yoke portion. As a result, the pattern to be used in forming the second yoke portion can be fabricated precisely.
Moreover, in the thin film magnetic head having an extremely narrowed recording track width through forming the second pole portion and the second yoke portion independently, the second yoke portion can be formed so as to have its vertical end (parallel end to the ABS) in the side of the ABS.
The second type of manufacturing method relates to a method for manufacturing a thin film magnetic head comprising a slider having an air bearing surface on its medium opposing surface and a thin film magnetic head element having a first magnetic film, a coil film, an insulating film, a gap film and a second magnetic film,
the first magnetic film including a first pole portion composed of its edge portion in the side of the air bearing surface and a first yoke portion continuing to the first pole portion and extending backward from the first pole portion,
the gap film being provided at least on the first pole portion,
the insulating film being provided above the first yoke portion and supporting the coil film,
the second magnetic film including a second pole portion opposing to the first pole portion via the gap film and a second yoke portion of which one end continues to and rises up on the second pole portion and of which the other end is joined with the first yoke portion at its rear portion, comprising of the steps of:
forming, after forming the first magnetic film, the gap film, the coil film, the insulating film and the second pole portion, a plate underfilm on their exposed surfaces,
forming a base organic resin film on the plate underfilm
applying a negative type photoresist film on the base organic resin film,
forming a resistframe to define a pattern for forming the second yoke portion through exposing and developing for the negative type photoresist film,
removing the part of the base organic resin film uncovered with the resistframe, and
forming a plate film to constitute the second yoke portion.
In this second type of manufacturing method, since the negative type resistfilm is used instead of the positive type resistfilm, the same effects as in the above first type of manufacturing method can be exhibited. Moreover, in this manufacturing method, since the base organic resin film is formed on the plate underfilm, the negative type resistfilm can be joined with the plate underfilm indirectly via the base organic resin film, and thus, is prevented from being peeled off.
The other objects, configurations and advantages will be explained in detail, with reference to the attaching drawings in embodiments.